1. Field of the Invention
The present invention relates to communication field, more particularly, relates to method and apparatus for receiving paging information.
2. Description of Prior Art
With the rapid development of communication technology, interpersonal information communication becomes more frequent. Sometimes, one cell phone is not enough, especially for those working in the fields of sales and management, and people need two, three or more cell phones at the same time. However, it is not convenient to carry many cell phones, which leads to the emergence of multi-card multi-standby cell phone. The multi-card multi-standby cell phone has only one phone body, but multiple SIM (Subscriber Identity Module/UIM, User Identity Model) card, which is much more convenient compared with carrying multiple cell phones.
Globe System of Mobile Communication (GSM) is the most widely used mobile communication system in the world. In GSM network, if a user needs multiple cell phone numbers for one cell phone, there are several options:
1. Multi-card single-standby system: one cell phone can take two or more than two SIM cards, while only one SIM card can be in service (in traffic) at a time. A hardware circuit is used to switch cards, and normally the single-standby card is selected after power-on. Normally, multiple SIM cards in the cell phone can not be dynamically switched in working mode because of protocol stack, and it is required to reboot the cell phone system (mainly to start the cell phone's protocol stack/upper layer software, etc.) to switch cards.
2. Multi-card multi-standby system: the multi-card multi-standby system overcomes the limitation of the conventional multi-card single-standby system, which enables multiple SIM cards in one cell phone to be in service (in traffic) at the same time. The multi-card multi-standby system is similar to multiple cell phones, which is much more useful than multi-card single-standby system.
In the early time, a multi-card multi-standby cell phone contains multiple communication systems (normally two communication systems), each of which includes respective radio frequency, base band and protocol stack. The multi-card multi-standby cell phone which contains multiple communication systems achieves simultaneously standby and service for multiple phone numbers, which can also be named as a multi-card multi-standby multi-pass system. However, multiple communication systems add costs and power consumption to cell phones, and require more space inside cell phones which leads to large phone size and inconvenience. For RF modules, because of co-channel interference, one RF module is normally placed on the top of a cell phone and the other at the bottom to reduce interference. The distance between the two antennas should be more than 100 millimeters.
Later multi-card multi-standby cell phones can be named as multi-card multi-standby single-pass system. Compared with the above system which contains multiple communication systems, the multi-card multi-standby single-pass system has only one communication unit. The multi-card multi-standby single-pass system requires upper layer protocol stack to work together by close integration. Although being complicated, the multi-card multi-standby single-pass system achieves multi-card multi-standby effect by monitoring paging information in turn under the control of protocol stack.
However, since there is only one communication unit, only one SIM card is able to use the communication unit to communicate with base station at a time, while other SIM cards are waiting. That is to say, when network sends paging information to the cell phone, only one SIM card is monitoring the paging information at a time. Therefore, it is possible for waiting SIM cards to miss paging information.
Chinese patent application No. 200780000267.9 discloses a transmitting method and a receiving method for wireless signal. When quality of user link is lower than the predetermined low threshold, using idle time slot on other carriers corresponding the user initial occupying carrier slot in the current cell to transmit/receive user signals; when quality of the user link is higher than the predetermined upper threshold, releasing the time slot of the user occupying on the other carriers. Using these methods, the quality of the user link is enhanced while saving network resource. However, it is unable to receive paging information by these methods. These methods are unable to help identify if the waiting SIM cards have incoming service (incoming traffic).